Dear Sir. Concerning your issue about the suitable method to dissolve the chitosan. An improved method of preparing water soluble chitosan was studied by N-acetylation with acetic anhydride. Its merits were a simple processing technique, very short reaction time, little agent, high molecular weight of the product, and good water solubility. Experiments showed that the amount of acetic anhydride was the most important factor affecting the N-acetylation degree of the chitosan. Chitosan is soluble at 1% in 1% acetic, adipic, formic, lactic, malic, propionic, or succinic acid. Formic acid has proved to be a good solvent over the entire acid concentration range from 0.25 to 50%, although at the extremes of this range, solutions contain gel particles. Solubility in "mineral" acids is limited. It is soluble only within the acid concentration range from 0.15 to 1.1%. It is insoluble in phosphoric, or sulfuric acid. Chitosan is insoluble in neutral or alkaline media. To be effective, Chitosan must first be dissolved into an aqueous solution. In applications additional acids may be needed to maintain pH below7 or Chitosan will precipitate out. As an example, for a 1% solution , disperse 1 gram of Chitosan in 50 ml of water with a high-speed stirrer, and while agitation is continuing, add 50 ml 2% acid. Stir for 30 minutes or until dissolution is complete. The following below links may help you in your analysis:

http://onlinelibrary.wiley.com/doi/10.1002/app.13537/abstract

http://www4.mpbio.com/ecom/docs/proddata.nsf/(webtds2)/150597

Thanks

Dear Sir. Concerning your issue about the suitable method to dissolve the chitosan. An improved method of preparing water soluble chitosan was studied by N-acetylation with acetic anhydride. Its merits were a simple processing technique, very short reaction time, little agent, high molecular weight of the product, and good water solubility. Experiments showed that the amount of acetic anhydride was the most important factor affecting the N-acetylation degree of the chitosan. Chitosan is soluble at 1% in 1% acetic, adipic, formic, lactic, malic, propionic, or succinic acid. Formic acid has proved to be a good solvent over the entire acid concentration range from 0.25 to 50%, although at the extremes of this range, solutions contain gel particles. Solubility in "mineral" acids is limited. It is soluble only within the acid concentration range from 0.15 to 1.1%. It is insoluble in phosphoric, or sulfuric acid. Chitosan is insoluble in neutral or alkaline media. To be effective, Chitosan must first be dissolved into an aqueous solution. In applications additional acids may be needed to maintain pH below7 or Chitosan will precipitate out. As an example, for a 1% solution , disperse 1 gram of Chitosan in 50 ml of water with a high-speed stirrer, and while agitation is continuing, add 50 ml 2% acid. Stir for 30 minutes or until dissolution is complete. The following below links may help you in your analysis:

http://onlinelibrary.wiley.com/doi/10.1002/app.13537/abstract

http://www4.mpbio.com/ecom/docs/proddata.nsf/(webtds2)/150597

Thanks

Chitosan is soluble at 1% in 1% acetic, adipic, formic, lactic, malic, propionic, or succinic acid.

Dear K S Rajkumar,

Please check the following.

Regards

SM Najim

http://www.mdpi.com/1422-0067/14/2/4174/pdf

https://core.ac.uk/download/pdf/11958295.pdf

http://cdn.intechopen.com/pdfs/16199/InTech-Characterization_and_properties_of_chitosan.pdf

https://www.researchgate.net/publication/223454608_Chitin_and_Chitosan_Polymers_Chemistry_Solubility_and_Fiber_Formation 

Article Chitin and Chitosan Polymers: Chemistry, Solubility and Fibe...

which is the best suitable solvent is used for solubility of chitosan for making nanoparticels